Hi all,
I’m wondering what I’ve done wrong in my sketch because I get a strange output.
I’m testing a DIY encoder and printing the counts and rpms every second. After the 32nd print to the screen, or 32nd second, the print output skips the second timer and prints continously. I checked the timer output and it jumps from 1001 to 65537 after 32 seconds. Am I missing something regarding the use of millis() timers? Thanks for the help.
Here’s the code:
// This is for testing the output of a motor encoder using a slotted
// optical switch as a sensor and an encoder wheel with 20 slots.
int sensorPin = 2;
int potVal = 0;
int potPin = A0;
int counter = 0; // counter for the number of sensor inputs.
int sensorState = 0; // current state of the sensor counter.
int lastSensorState = 0; // previous state of the sensor counter.
int time = 0; // timer for counter
int revsPersec = 0; // counter for revolutions per second
int revsPermin = 0; // counter for rpms
int dirPinAM1 = 3;
int dirPinBM1 = 4;
int enMotor1 = 6; // enable motor
int lSpeed = 0;
void setup() {
// initialize the sensor pin as input:
pinMode(sensorPin, INPUT);
pinMode(potPin, INPUT);
// initialize the counter timer
time = millis();
Serial.begin(9600);
}
void loop() {
potVal = analogRead(potPin);
lSpeed = map(potVal, 0, 1023, 0, 255);
analogWrite(enMotor1, lSpeed);
digitalWrite(dirPinAM1, HIGH);
digitalWrite(dirPinBM1, LOW);
// read the sensor input pin:
sensorState = digitalRead(sensorPin);
// compare the sensorState to its previous state
if (sensorState != lastSensorState) {
// if the state has changed, increment the counter
if (sensorState == HIGH) {
counter++;
}
}
// save the current state as the last state,
//for next time through the loop
lastSensorState = sensorState;
if(millis() - time > 1000){
Serial.println(millis() - time);
// after 1 second, calculate the revs per sec and rpms
revsPersec = counter/20;
revsPermin = revsPersec*60;
Serial.print("Counts per second ");
Serial.println(counter);
Serial.print("Revs per second ");
Serial.println(revsPersec);
Serial.print("RPM ");
Serial.println(revsPermin);
// reset the counters and timer for next second
counter = 0;
revsPersec = 0;
revsPermin = 0;
time = millis();
}
